Charlotte's smog problem seems to be getting better, though it's a difficult problem to measure.

However, regulators can tell us there's less sulfur dioxide and nitrogen-oxide in the air, and ozone levels are responding according to plan. That's great news for all us breathers in North Carolina, don't you think?

Not only is the reduction in air pollution good for our health, it's good for our economy too. Who wants to relocate a business or their family to a city known for toxic air? Plus, if we want to continue receiving federal dollars for our pot hole-y roads, we've got to get our air quality issues under control. Good roads lead to good things; the Romans figured that one out.

Plus, I don't know about you, but a summer without "code orange" air quality warnings sounds really nice.

Keep up the good work, anti-smog legislation.

The $2.9 billion N.C. utilities will spend to obey a landmark anti-smog law has sent power-plant emissions plummeting.

But where's the proof, a conservative think tank in Raleigh asked Friday, that the money has also cleaned our air?

"I don't know if they're overstating or understating (benefits), but they don't know either," said Roy Cordato, an economist at [The John Locke Foundation]. "I just hope that their feet are held to the fire."

The N.C. Division of Air Quality countered that smog is trending steadily down, reaching the lowest point statewide on record last year. Mecklenburg County, however, still struggles to meet federal standards.

Signs of success came soon after the first controls were installed in 2005 and 2006, she said. Smog levels climbed in fewer places in the spring. Fine-particle pollution stayed within federal limits across most of the state.

Actual ozone levels now are extremely close to what computer models predicted in 2002 when the law was enacted, she said.

The act mandated a 77 percent cut in nitrogen-oxide emissions by 2009 and a 73 percent cut in sulfur dioxide by 2013. It estimated costs to utilities at $2.3 billion.

Under the state legislation, Duke Energy has reduced its sulfur-dioxide emissions by 80 percent. Nitrogen oxides fell by about half between 1997 and 2002, under a federal ozone mandate, and have dropped another 77 percent under the state legislation.

The last pieces, sulfur dioxide "scrubbers" at Duke's Cliffside power plant in Rutherford County, are being installed now, two years before a 2013 deadline.

"We're getting at the right emissions," said Kris Knudsen, a Duke Energy air-quality official.

While federal rules also required Duke to install pollution controls, Knudsen said Clean Smokestacks prompted Duke to do more and install them on a quicker schedule.

The act's total cost to Duke: $1.8 billion, $500 million of which the utility will recover through a 7 percent N.C. rate increase approved in December.

Read the entire Charlotte Observer article, by Bruce Henderson, here.